In minimally invasive surgical procedures that use elongated instruments and videoscopic viewing of the surgery site, there is significant difficulty in knot tying and wound approximating. Traditional methods of wound closure routinely involve the use of individual hand-knotted sutures. The suture strands are directed through portions of tissue to be joined and formed into a single stitch, which is then knotted. However, due to the location of the area being sutured, the delicate nature of anatomical features, and the stiffness of the suture used, it can be difficult to tie uniform stitches to close the wound that do not unravel or tie off (or ligate) a vessel. Non-uniform stitches (i.e., stitches of varying tension) or varied bite size (depth into the tissue) can cause uneven healing, localized trauma, infection, and patient discomfort.
To reduce the discomfort and aid healing, it is desirable to secure sutures uniformly and close to a wound. Due to the stiffness of some sutures, knotting the sutures can be difficult, particularly when the tissue to be sutured is deep within the body. Typical knots may be relatively large and elevated above the tissue being sutured, which can increase patient discomfort.
It is also desirable in many surgical procedures where sutures are used, to reduce the size of, or eliminate, the knot bundle associated with a knotted suture and to minimize the amount of foreign material in the body. The knot bundle can become an irritant and retard the healing process and cause discomfort or pain for the patient. The knot bundle can also be a source of infection.
Methods known in the art to overcome these problems include various suture securing devices such as buttons, and methods of fusing synthetic sutures. Although buttons can produce sutures with even tension and without the concomitant dexterity of knot tying, their elevated location above the wound or within the body cavity can cause irritation and discomfort. Furthermore, there is a risk of button migration, since they are discrete objects in the body.
Suture fusion techniques, whereby synthetic polymer suture strands are melted together by the application of heat or other energy to the sutures, are known in the art. Examples of devices to perform such suture fusion are disclosed in U.S. Pat. No. 5,417,700, assigned to the assignee of this application and incorporated herein by reference. However, some polymeric sutures are not amenable to this process. For example, braided or multi-filament sutures may not completely fuse since spaces between the individual strands may interfere with the heat or energy transfer needed for fusion to occur. As a result, the sutures may be incompletely fused, and the resulting joint may fail.
It would be advantageous to provide suture and tissue joining devices which are fusible to and/or around sutures and other structures, including living tissue, so as to avoid the need for suture knots.